<template>
      <!-- 输入框 -->
      <header class="header">
      <h1>小黑记事本</h1>
      <input 
      @keyup.enter="handleAdd"
      placeholder="请输入任务" class="new-todo" v-model="todoName"/>
      <button @click="handleAdd" class="add">添加任务</button>
    </header>
</template>

<script>
export default {
    data(){
        return {
            todoName:''
        }
    },
    methods:{
        handleAdd(){
            if(this.todoName.trim() === ''){
                alert('任务名称不能为空')
                return
            }
            this.$emit('add',this.todoName)
            this.todoName=''
        }
    }
}
</script>

<style>

</style>